Planetary vibrator



Aug. 9, 1966 B. N. HOFFSTROM 3,265,367

PLANETARY VIBRATOR Original Filed April 20, 1961 4 Sheets-Sheet 1 INVENTOR 80 N. Hoffst om g- 5 B. N- HOFFSTROM 3,265,367

PLANETARY V I BRATOR Original Filed April 20, 1961 4 Sheets-Sheet 2 INVENTOR 80 N. Hoffstrom BY 'mzmz/w WM (fig ATTORfiEYS Aug. 9, 1966- B. N. HOFFSTROM PLANETARY VIBRATOR 4 Sheets-Sheet 5 Original Filed April 20. 1961 INVENTOR B0..N. Hoffstrom BY dmwfl r/Mk/M mfm Aug. 9, 1966 a. N. HOFFSTROM 3,265,367

' PLANETARY VIBRATOR Original Filed April 20, 1961 4 Sheets-Sheet 4 INVENTOR 50 N. Hoffstrom Mina, M 77620 wzj ATTORNEYS United States Patent 3,265,367 PLANETARY VIBRATOR Bo N. Hoifstrom, Santa Monica, Calif., assignor to Douglas Aircraft Company, Inc., Santa Monica, Calif. Original application Apr. 20, 1961, Ser. No. 104,353, now Patent No. 3,211,262. Divided and this application Mar. 10, 1965, Ser. No. 458,526

3 Claims. (Cl. 259-72) This application is a division of co-pendin-g application, Serial No. 104,353 filed April 20, 1961, for Planetary Mechanisms.

This invention relates to rotary planetary mechanisms effective to receive input energy or to transmit the input energy to another portion of the system in which they are placed.

The invent-ion functions as a device for transforming the rotary energy applied to the drive shaft to vibratory motion which may be utilized to actuate a variety of devices such as a shaker table or to produce wave motion in a surrounding fluid medium, for example to generate sound or to operate an ultrasonic cleaner,

It is an object of the present invention to provide novel ultrasonic cleaners incorporating as a principal component the improved planetary mechanism of the present invention.

It is an additional object of the present invention to provide novel sound generators also incorporating the improved planetary mechanism of the present invention.

It is a further object of the present invention to provide improved rotary planetary devices effective to transform rotary input energy into vibratory motion with an efiiciency considerably higher than heretofore obtainable in the art.

In its basic form the present invention comprises a gearless planetary mechanical system including an inner sun ring, a number of planets carried :by a spider or cage, and an outer ring surrounding the planets. The planets and the inner and outer ring members are all provided with smooth drive surfaces and accordingly may be termed toothless gears.

The inner surface of the outer ring, which is engaged by the planets, is provided with a series of cam surfaces.

Since the planet members and the inner sun member are of cylindrical form, the annular channel traversed by the planet members is of varying radial dimensions. Thus, when the sun member is driven, thus rotating or tending to rotate the planet gears and the spider or cage which carries them, the planets, as they engage the cam surfaces, exert a force on the outer ring gear which has a circumferential component and a radial component. Either the radial component or the circumferential component of force acting on the outer ring may be used effectively depending upon the apparatus with which the planetary mechanism is associated.

In cases where the input torque is maintained at a constant level above that necessary to move the planet gears over the cam lobes on the outer ring, the mechanism acts as a variable torque transmitting device to produce rotary oscillation in the outer ring member which may be utilized as a drive mechanism for a shaker table, a vibratory feed mechanism or in other applications where the production of a high speed oscillating motion is desirable.

The radial component of force developed in the mechanism may be utilized effectively by restraining all ciroumferential motion of the outer ring member. In this case, high frequency radial motion will be induced in the outer ring member which may be transmitted to a surrounding fluid medium to produce wave motion of a predetermined character in this medium, for example to operate an ultrasonic cleaner or to produce sound.

Patented August 9, 1966 "ice Additional objects and advantages of the present invention will become apparent as the description proceeds in connection with the accompanying drawings in which:

FIGURE 1 is a transverse section of the apparatus of the present invention in one of its basic forms;

FIGURE 2 is a section taken along line 22 of FIG- URE 1 showing details of a mechanism for variably restricting the rotary movement of the spider carrying the planet members;

FIGURE 3 is an enlarged fragmentary section taken along line 33 of FIGURE 1 showing the configuration of the cam surfaces on the outer ring member;

FIGURE 4 is a front elevation of the apparatus as incorporated in a shaker table drive mechanism;

FIGURE 5 is a vertical section through an ultrasonic cleaner unit embodying the drive mechanism of the present invention;

FIGURE 6 is a transverse section taken along line 66 of FIGURE 5; and

FIGURE 7 is a central vertical section of a sound gen erator embodying the novel planetary mechanism of the present invention.

Referring now more particularly to the drawings, in the form of the invention shown in FIGURES 1, 2 and 3, the planetary mechanism is enclosed within a dish-shaped housing member indicated generally at 20 closed by a plate-like cover member 22 detachably secured to the main housing member 20 by a plurality of bolts 24. A circumferential flange 26 of the main housing member 20 is secured by a plurality of bolts 28 to any suitable support assembly 30 which has suflicient rigidity and mass to prevent rotary or oscillating motion of the housing 20.

A relatively heavy input shaft 32 is mounted for rotation coaxially of the housing member 20 on a front bearing assembly 34 carried in a central opening 36 in the cover plate 22 and a rear bearing assembly 38 supported on a mounting ring 40 press-fitted or otherwise suitably mounted on a boss 42 formed integrally with the bottom wall 44 of the housing member .20. A suitable sealing mechanism 46 is provided adjacent the outer bearing 34 to prevent the entry of dirt and other foreign matter. The enlarged central hubportion 48 of the shaft 32 is provided with a plurality of radial notches 50 into which slidably extend tongue members 52 formed integrally with the inner periphery of the sun ring 54. It will be noted that there is a slight annular clearance between the outer periphery of the hub portion 48 and the inner periphery of the sun ring 54. This clearance, coupled with the tongue and notch connection between the two members, permits the sun ring 54 to flex radially to some extent in operation and to center itself automatically with respect to the remainder of the mechanism. The sun member 54 is held in axial position on the hub 48 by locking rings 56 carried by the hub member and bearing against wear rings 58 which engage the side surfaces of the adjacent portions of the hub and ring.

The outer ring member 60 is provided with a plurality of radially projecting tongues 62 which are slidably received in correspondingnotches 64 in the circumferential wall portion 66 of the main housing member 20. Again, a slight radial clearance is provided between the outer surf-ace of the ring member 60 and the inner surface of the housing wall 66 to permit radial flexing of the ring 60 and to permit the ring to become centered automatically around the axis of the input shaft 32. The ring 60 is held against axial motion by ridges 68 and 70 projecting from the bottom wall 44 of the housing 20 and the inner surface of the cover plate 22, respectively.

The planets are of identical construction, each of the planets 72 being of hollow cylindrical form and being rotatably mounted at equally ciroumferentialy spaced jent invention has many diverse applications.

locations around the axis of the input shaft 32 on resilient discs 74 carried by a collar 76 journalled on a stub shaft 78 formed integrally with a spider 80. 'Iihe collars 76 are retained on the shaft 78 by end plates 82 secured to the shafts by bolts 84. The stacks of resilient rings 74 are held against shoulders 86 on the collars 76 by lock rings 88. Annular shoulders 90 on the inner periphery of the planet ring 72 are engaged by the outer periphery of the stacks of resilient rings 74 to prevent excessive axial play of the planets. The resilient mounting of the .planets is an important feature of the invention for reasons discussed in detail below.

The hub of the spider 80 is supported on a bearing assembly 92 carried by an "extension of the input shaft 32, the bearing being held against shoulders in the respective members by locking rings 94 and 96. In this form of the invention, the spider 80 is resiliently restrained against free rotation and is biased toward a predetermined angular position. This is accomplished by oppositely acting sets of leaf springs 98, and 102. The springs 98 extend diametrically across the apparatus through a slot 104 formed in the housing boss 42. The outer ends of the springs bear against a pair of symmetrically positioned .rollers 106 which are journ'alled on stub shafts 108 formed integrally with spider 80 and held in place by end plates 110 attached to the stub shafts 108 by screws 112. Because of the relative positioning of the springs and the rollers 106, the springs 98 are effective to yieldably oppose rotation of the spider in a counterclockwise direction as viewed in FIGURE 2. Rotation of the spider in this direction is positively limited by a pair of symmetrically opposite stops 114 formed integrally with the housing 20 and projecting into the path of the ends of the springs 98. The outer ends of the slot 104 are cut away at 116 to permit the necessary deflection of the spring 98.

The relatively light sets of springs 100 and 102 extend through radial slots 118 and 120 in the housing boss 42 and their inner ends are bent as shown to retain them in place. The outer ends of the springs 100 and 102 bear .against a pair of symmetrically opposite rollers 122 journalled on stub shafts 124 projecting from the spider 80 in the same manner as the rollers 106. The spring sets .100 and 102 are effective to resiliently oppose motion of the spiderin a clockwise direction as viewed in FIGURE 2, the limit of motion in this direction being determined by stops 126 carried by the housing 20 and projecting into the path of the springs 100 and 102 as they are deflected. Again, the outer ends of slots 118 and 120 are cut away as at 128 and 130 to facilitate deflection of the springs.

As best shown in FIGURE 3, the inner surface of the outer ring 60 is provided with a plurality of cams, the cams being the same in number and having the same circumferential spacing as the planets 72. In the example .shown, 12 cams are employed, each having a circumferential length of 30. Each cam comprises a peak 132, a steep cam rise 134, a dwell portion 136 and a shallow rise section 138. In a typical case the shallow rise section has an angular extent of 22, the dwell extends 5 and the steep rise extends 3 along the inner circumference of the ring 60. The sets of springs are so arranged with respect to the cam surfaces that the former are unloaded as shown in FIGURE 2 when the planets are in engagement with the cam peaks 132 as shown in FIGURE '3. The heavy springs 98 are deflected in a counterclockwise direction from the position shown in FIGURE 2 and the relatively light springs 100 and 102 are deflected when the planets are moved in the opposite directions. Further, the stops 114 and 126 are so positioned that the planets may be circumferentially shifted in either direction from the position shown until they are opposite the .dwell portion of the cam in which location the planets run free between the sun ring 54 and the outer ring'60.

As stated above, the planetary mechanism of the pres- One of 4. these is a shaker table drive mechanism as shown in FIG- URE 4 to which detailed reference will nowbe made. In this form the planetary drive system indicated generally at 142 is identical with the previously described unit except that the cam surfaces on the outer ring are extending cars 148 and 150 formed integrally with the housing of the planetary mechanism 142 are pivotally secured to arms 152 and 154, respectively, depending from shaker tables 156 and 158. The planetary drive mechanism 142 and the shaker tables 156 and 158 are normally maintained in the position shown by springs 160 and 161 coiled between shoulders 162 and 163 on the respective arms 152 and 154 and the base plate 146. Rotation of the planetary mechanism 142 away from this neutral position is limited by contact of the lower ends of the arms 152 and 154 with the base plate 146, the clearance at these points being selected to suit the requirements of the particular installation. The mechanism may be driven by any suitable source of power (not shown) drivingly connected to the input shaft 164 of the planetary drive mechanism 1142.

Upon rotation of the shaft 164, for example in a clockwise direction, the planets individually begin to rotate in a counterclockwise direction carrying the spider in a clockwise direction and tending to carry the housing of the mechanism 142 in a clockwise direction as the planets pass upwardly along the cam rises. Thus the housing is rotated slightly in a clockwise direction lowering the shaker table 158 and raising the shaker table 156. When the mechanism is being started, the motion continues until the lower end of the arm 154 contacts the base plate 146. Continued rotation of the drive shaft causes the planets to pass over the peaks of the cams tending to accelerate travel of the spider in a clockwise direction, the reaction rotating the housing of the mechanism 142 in the opposite direction thus raising the shaker table 158 and lowering the shaker table 156. In the continued rotation of the drive'shaft 164, the mechanism 142 oscildates with a frequency which is a function of the speed of the drive shaft, the number of planets and the number of cam surfaces employed, all of which factors can be varied to suit the requirements of a particular installation. It is to be understood that when the mechanism is operated at its rated speed, the lower ends of the arms 152 and 154 will be out of contact with the base plate at all times.

To facilitate starting, a clutch and flywheel will be preferably incorporated in the drive train. This shaker table drive mechanism is capable of handling extremely large loads and since it operates with substantially perfect elasticity, it absorbs very little power.

FIGURES 5 and 6 to which detailed reference will now be made illustrate the utilization of the planetary mechanism of the present invention as the drive mechanism for an ultra-sonic cleaner. In this form of the invention the planetary drive mechanism is enclosed in a main housing member to which a cover plate 172 is attached as by screws 174. The rigid sun member 176 may be formed integrally with the drive shaft 178 mounted for rotation coaxially of the housing member 170 and cover plate 172 on bearings 180 and 182, the

former being supported on a boss 184 formed integrally with housing member 170 and the latter being supported on a flange 186 formed integrally with the cover .plate 172. To decrease the power requirements and to promote smoothness and stability of operation, a flywheel 188 is splined to the drive shaft 178 and is received in the space provided by the cover member 172.

The outer cam ring 190 is formed integrally with the main housing 170 and is separated from the rigid housing portions by thin-walled skirts 192 and 194.

The solid cylindrical planets 196 are supported for free rotation in the annular space between the sun member 176 and the ring portion 190 in a cage indicated generally at 198 which is similar to the conventional roller. bearing cage. The cage 198 comprises an essentially cylindrical body portion having end flanges 202 and 204 which engage the opposite sides of the heavy ring portion 190 to prevent undue axial travel of the cage. The cage is provided with a plurality of radial slots 206 in which the planets 196 are loosely received. Formed integrally with the main body portion of the cage are discontinuous ridges 208 and 210, the thickness of the body portion through the ridges being slightly less than the space between the inner su-rface of the cam ring 190 and the outer surface of the sun member 176 to permit free travel of the cage while preventing undue radial motion. Sealingly secured to the main housing member 170 as by a plurality of bolts 212 is a container 214 which may be filled with any suitable fluid, for example water.

As in the embodiment of FIGURE 4, the inner surface of the outer ring 190 is formed with a plurality of symmetrical cams, the number and circumferential spacing of which corresponds to the number and circumferen tial spacing of the planets 196. In operation the container 214 is filled with a liquid such as water in which the articles to be cleaned are immersed and the drive shaft 178 is driven by any suitable power source (not shown).

As the drive shaft rotates, vibrations of an ultrasonic frequency are generated in the ring 190 which establish ultrasonic wave motion in the surrounding body of liquid, which, as is well known in the art, are eflective to loosen and remove dirt from the articles to be cleaned. Because of the utilization of the thin-walled skirts 192 and 194, the induced vibrations are confined largely to the relatively heavy ring portion 190 and are not transmitted to the remainder of the mechanism. In a typical case the shaft 178 will be driven at a speed in the neighborhood of 100,000 r.p.m. When the shaft is driven at this speed and some 24 planets 196 are utilized, vibrations well into the ultrasonic range (40,000 cycles per second) will be induced in the surrounding fluid body. It must be observed that the maximum frequency that can be induced in the heavy ring portion 190 equals its natural frequency when swinging in its basic radial mode. This is a function of its diameter, wall thickness, modulus of elasticity, and mass density. For example, the maximum frequency (f) in cycles per second for a steel ring of a suitable wall thickness having an outer diameter of D inches is given by the formula:

Thus, in the above example the outer diameter of the cam ring must not exceed 1.29 inches for a 40,000 c.p.s. frequency.

The mechanisms of FIGURES 5 and 6 may be adapted for use as a sound generator for directed energy by adding to the housing 170 a fairing 216 of paraboloid form and substituting for the container 214 an exponential horn 218 of well-known form as shown in FIGURE '7. The main drive mechanism may otherwise be of the same form as that shown in FIGURES 5 and 6. However it may be driven at a speed such that the vibrations induced in the air within the horn 218 will be in the range of audible sound.

The invention may be embodied in other specific forms Without departing from the spirit or essential characteristics thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description,

and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

What is claimed and desired to be secured by United States Letters Patent is:

1. Drive means for inducing wave motion in a body of fluid in a container comprising a housing mounted within said container, a sun member rotatably mounted in said housing, said housing having a ring portion surrounding said sun member, a cage rotatably mounted in said housing, a plurality of planets carried by said cage for movement in the annular space between said sun member and said ring member, and said ring member having a plurality of cam surfaces engageable by said planets which effectively vary the radial width of said space the maximum radial width of said space being essentially equal to the diameter of said planets and the minimum radial width of said space being less than the diameter of said planets whereby, upon rotation of said sun member, said ring portion of said housing is radially deflected to induce wave motion in the body of fluid surrounding said housing within said container.

2. Drive means for inducing wave motion in a body of fluid in a container comprising a housing mounted within said container, a sun member in said housing, said housing having a ring portion surrounding said sun member, a cage rotatably mounted in said housing, a plurality of planets carried by said cage for movement in the annular space between said sun member and said ring member, said ring member and said sun member being solid and being so formed as to provide, when unstressed, a radial space therebetween of periodically varying radial width, the maximum radial width of said space being essentially equal to the diameter of said planets and the minimum radial width of said space being less than the diameter of said planets, and means for moving said cage and said planets circumferentially through said space whereby said ring portion of said housing is radially deflected to induce wave motion in the body of fluid surrounding said housing within said container.

3. Drive means for inducing wave motion in a body of fluid in a container comprising a housing mounted within said container, a solid sun member rotatably mounted in said housing, a solid ring surrounding said sun member, said ring being connected to said housing by relatively thin-walled skirt portions formed integrally with said ring and said housing, a cage mounted for rotation in said housing, a plurality of planets carried by said cage for movement through the annular space between said sun member and said ring, said sun member and said ring being so formed as to provide, when unstressed, a radial space therebetween of periodically varying radial width, the maximum radial Width being essentially equal to the diameter of said planets and the minimum radial width being less than the diameter of said planets whereby upon rotation of said sun member said planets move ci-rcumferentially through said radial space and said ring is radially deflected to induce wave motion in the body of fluid surrounding said housing within said con tainer.

References Cited by the Examiner UNITED STATES PATENTS 1,417,219 5/1922 Warren 259-59 1,519,153 12/1924 Mitton 25959 1,581,780 4/1926 Brass 25959 2,607,568 8/1952 Seavey et al.

2,608,391 8/1952 Seavey et al.

2,826,396 3/1958 Murdoch 259-72 3,180,626 4/ 1965 Mettler 259-72 WALTER A. SCHEEL. Primary Examiner.

JOHN M. BELL, Assistant Examiner. 

1. DRIVE MEANS FOR INDUCING WAVE MOTION IN A BODY OF FLUID IN A CONTAINER COMPRISING A HOUSING MOUNTED WITHIN SAID CONTAINER, A SUN MEMBER ROTATABLY MOUNTED IN SAID HOUSING, SAID HOUSING HAVING A RING PORTION SURROUNDING SAID SUN MEMBER, A CAGE ROTATABLY MOUNTED IN SAID HOUSING, A PLURALITY OF PLANETS CARRIED BY SAID CAGE FOR MOVEMENT IN THE ANNULAR SPACED BETWEEN SAID SUN MEMBER AND SAID RING MEMBER, AND SAID RING MEMBER HAVING A PLURALITY OF CAM SURFACES ENGAGEABLE BY SAID PLANETS WHICH EFFECTIVELY VARY THE RADIAL WIDTH OF SAID SPACE THE MAXIMUM RADIAL WIDTH OF SAID SPACE BEING ESSENTIALLY EQUAL TO THE DIAMETER OF SAID PLANETS AND THE MINIMUM RADIAL WIDTH OF SAID SPACE BEING LESS THAN THE DIAMETER OF SAID PLANETS WHEREBY, UPON ROTATION OF SAID SUN MEMBER, SAID RING PORTION OF SAID HOUSING IS RADIALLY DEFLECTED TO INDUCE WAVE MOTION IN THE BODY OF FLUID SURROUNDING SAID HOUSING WITHIN SAID CONTAINER. 